In the brain, neurotransmitters or neuromodulators play pivotal roles in chemical synaptic transmission and consequently, monitoring their dynamics, especially in vivo, is critical for understanding their physiological- or pathophysiological roles at molecular, cellular, and circuit levels during behaviors and/or during diseases. We recently developed genetically-encoded GPCR-activation based (GRAB) sensors capable of reporting dynamics of acetylcholine, dopamine and norepinephrine with rapid kinetics, chemical- and cell-specificity in multiple organisms in vivo. Here, we explored the usage of G protein derivatives, either mini-G proteins or C-terminal peptides of Gα subunit to engineer new GRAB sensors. We found that the conformational changes mediated by mini-G proteins interacting with GPCRs, or Gα Cterminal peptides interacting with GPCRs could be harnessed to regulate fluorescence outputs of a GPCR fused circular permuted GFP (cpGFP). In addition, inter-molecular fusion of Gα C-terminal peptides significantly suppressed ectopic activation of G protein signaling in a GRAB acetylcholine sensor. Finally, we showed Gα C-terminal peptides fusion strategy could be applied to generate various GRAB sensors for small molecular compounds or neuropeptides.

Date Published: 1 March 2019
PDF: 6 pages
Proc. SPIE 10865, Neural Imaging and Sensing 2019, 108650N (1 March 2019); doi: 10.1117/12.2514631

Published in SPIE Proceedings Vol. 10865:
Neural Imaging and Sensing 2019
Qingming Luo; Jun Ding; Ling Fu, Editor(s)